/*
 * Copyright:  2018 smarabbit studio.
 *
 *  Licensed under the Confluent Community License; you may not use this file
 *  except in compliance with the License.  You may obtain a copy of the License at
 *
 *  http://www.confluent.io/confluent-community-license
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OF ANY KIND, either express or implied.  See the License for the
 *  specific language governing permissions and limitations under the License.
 *
 *  @作   者： 黄开晖 (117227773@qq.com)
 *  @日   期:  2019年1月7日
 */

package com.massyframework.beanskin.springboot.beancontext.provider;

import org.springframework.context.ConfigurableApplicationContext;

import com.massyframework.beanskin.assembly.Assembly;
import com.massyframework.beanskin.assembly.AssemblyContextDelegate;
import com.massyframework.beanskin.assembly.handling.ActivationHandler;
import com.massyframework.beanskin.assembly.handling.HandlerRegistration;
import com.massyframework.beanskin.springboot.beancontext.DependencyServiceBeanDefinitionRegistryPostProcessor;
import com.massyframework.beanskin.springboot.beancontext.DependencyServiceInitializer;
import com.massyframework.beanskin.springboot.beancontext.SpringBeanContextAdapter;
import com.massyframework.beanskin.springboot.beancontext.StandloneApplicationContextFactory;
import com.massyframework.beanskin.util.classloading.ClassLoaderUtils;

/**
 * {@link StandloneHandler} 提供基于独立Spring容器的抽象语义。
 */
public final class StandloneHandler extends DependencyServiceBeanDefinitionRegistryPostProcessor
		implements ActivationHandler {

	private volatile HandlerRegistration<AssemblyContextDelegate<SpringBeanContextAdapter>> registration;

	/**
	 * 构造方法
	 */
	public StandloneHandler() {
	}

	/**
	 * 启动,使得进入激活状态
	 *
	 * @throws Exception 启动时发生非预期例外
	 */
	@Override
	public synchronized void doStarting() throws Exception {
		if (this.registration == null) {
			Assembly assembly = this.getAssociatedAssembly();

			AssemblyContextDelegate<SpringBeanContextAdapter> delegate = null;

			SpringBeanContextAdapter adapter = this.createBeanContext(assembly);
			delegate = new AssemblyContextDelegate<>(adapter);
			delegate.init(this.getLifecycleManager());
			this.setAssemblyContext(delegate);

			ClassLoader contextLoader = ClassLoaderUtils.setThreadContextClassLoader(assembly.getModuleClassLoader());
			try {
				this.registration = this.getLifecycleManager().register(delegate);
			} finally {
				ClassLoaderUtils.setThreadContextClassLoader(contextLoader);
			}
		}
	}

	/**
	 * 已停止，退出激活状态
	 *
	 * @throws Exception 停止时发生非预期例外
	 */
	@Override
	public synchronized void doStopped() throws Exception {
		if (this.registration != null) {
			AssemblyContextDelegate<SpringBeanContextAdapter> context = this.registration.getHandler();
			this.registration.unregister();
			this.registration = null;

			ClassLoader contextLoader = ClassLoaderUtils
					.setThreadContextClassLoader(this.getAssociatedAssembly().getModuleClassLoader());
			try {
				context.getBeanContext().getApplicationContext().close();
			} finally {
				this.setAssemblyContext(null);
				ClassLoaderUtils.setThreadContextClassLoader(contextLoader);
			}
		}
	}

	/**
	 * 基于{@link Assembly} 创建Spring容器，并返回封装的适配器
	 * 
	 * @param assembly {@link Assembly}, 装配件
	 * @return {@link SpringBeanContextAdapter}
	 */
	protected SpringBeanContextAdapter createBeanContext(Assembly assembly) {
		StandloneApplicationContextFactory factory = new StandloneApplicationContextFactory();

		DependencyServiceInitializer<ConfigurableApplicationContext> initializer = new DependencyServiceInitializer<ConfigurableApplicationContext>(
				this);
		ConfigurableApplicationContext applicationContext = factory.createApplicationContext(assembly, initializer);
		SpringBeanContextAdapter result = new SpringBeanContextAdapter(applicationContext);
		return result;
	}
}
